Besides keeping the virus down, some antiretroviral drugs have another handy benefit—they can increase the levels of HDL cholesterol—the kind of cholesterol that can help you by reducing risk of coronary heart disease. As part of a larger study on antiretroviral therapy, researchers compared two antiretroviral drugs, nevirapine and efavirenz.

What the researchers wanted to know: Does nevirapine or efavirenz increase HDL more?

What they did: The main reason for the 2NN study was to compare different drug treatments, but researchers also planned to look at how different treatments changed patients' lipid profiles. For the study, patients who hadn't yet received antiretroviral therapy took different combinations of drugs. All took stavudine and lamivudine; then they were randomly assigned to get either nevirapine, efavirenz, or both. They had blood taken before treatment started, then periodically during the study.

What they found: HDL went up by 42.5 percent in patients taking nevirapine and by 33.7 percent for patients on efavirenz. (The difference between the two, while not huge, is statistically significant.) Total cholesterol and LDL cholesterol went up, too.

What the study means to you: One of the weird effects of HIV drugs is that they change the concentrations of different lipids in the body. This gives more detail about how that happens.

Caveats: The researchers didn't know whether patients had common risk factors for coronary heart disease, such as smoking, so it's possible that this could have confounded their data—for example, by chance, all of the smokers might have ended up in one treatment group, which would skew the results. But it's unlikely, since there were about 700 people.

Find out more: This work was done as part of the 2NN study, which you can read about at www.iatec.com

AIDSmeds.com explains the class of drugs called non-nucleoside reverse transcriptase inhibitors, or NNRTIs, of which nevirapine and efavirenz are members. If you want to learn more, they also explain the whole life cycle of the virus that causes AIDS and point out where different drugs block it.

Read the article: van Leth, F., et al. "Nevirapine and Efavirenz Elicit Different Changes in Lipid Profiles in Antiretroviral-Therapy-Naïve Patients Infected with HIV-1." Public Library of Science Medicine, online only. October 2004, Vol. 1, No. 1, e19.

Article online: http://medicine.plosjournals.org